FAL_SERVER and FAL_CLIENT parameter in Oracle dataguard

FAL_SERVER Parameter
FAL means fetch archive log. Its clearly indicate with name that fetch the archive log.
FAL_SERVER used to fetch archive log server for a standby database.
Value in FAL_SERVER parameter act as Oracle Net Service name which point to standby database.

FAL_CLIENT Parameter
FAL_CLIENT specifies the FAL(fetch archive log) client name that is used by the FAL service.
It configured for point the FAL Client.
Value in FAL_CLIENT is also an Oracle Net Service Name.

Example of using in Dataguard
We need tnsname.ora file which is having Oracle net service name configured for Primary and Standby site. Both has same tnsnames.ora file.

TNSNAMES.Ora file

TESTPR =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = PrimServer)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = testpr)
)
)


TESTDR =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP) (HOST = StandServer)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = testdr)
)
)


Configure FAL_Server and FAL_CLIENT on Primary and Standby
Configured the value onf FAL_SERVER and FAL_CLIENT on Primary and Standby site as follows:
On Primary Database

ALTER SYSTEM SET FAL_SERVER=;
ALTER SYSTEM SET FAL_CLIENT=;


ALTER SYSTEM SET FAL_SERVER=TESTDR;
ALTER SYSTEM SET FAL_CLIENT=TESTPR;


On Standby Database

ALTER SYSTEM SET FAL_SERVER=;
ALTER SYSTEM SET FAL_CLIENT=;


ALTER SYSTEM SET FAL_SERVER=TESTPR;
ALTER SYSTEM SET FAL_CLIENT=TESTDR;